US2035769A - Refrigerating machine - Google Patents

Description

March 31, 1936. c. STEENSTRUP REFRIGERATING MACHINE 2 Sheets-Sheet l Filed June 29, 1934 Inventor" Christian Steenstrup His Atborn ey.

March 31, 1936. c STEENSTRUP 2,035,769

REFRIGERATING MACHINE Filed June 29, 1934 2 Sheets-Sheet 2 Inventor:

b WW

y HisA torney.

Christi an Steen SbPup,

Patented Mar. 31, 1936 UNITED STATES PATENT OFFICE REFRIGERATIN G MACHINE Christian Steenstrup, Schenectady, N. Y., assignor to General Electric Company, a corporation of New York My invention relates to refrigerating machines. It is an object of my invention to provide a refrigerating machine including an improved evaporator which shall provide adequate cooling 5 and ice freezing capacity and shall require a minimum space within a refrigerator cabinet.

Another object of my invention is to provide in a refrigerating machine an L-shaped evaporator including an air cooling portion and a shelf for supporting freezing trays and the like, and having an improved arrangement for circulating refrigerant therein.

Another object of my invention is to provide in a refrigerating machine a flooded evaporator 15 having two portions and having an improved arrangement for producing circulation of liquid refrigerant therein.

Further objects and advantages of my invention will become apparent as the following de- 20 scription proceeds, and the features of novelty which characterize my invention will be pointed out with particularity in the claims annexed to and forming a part of this specification.

For a better understanding of my invention reference may be had to the accompanying drawings in which Fig.,1 is a sectional view of a household refrigerator cabinet having an evaporator embodying my invention; Fig. 2 is a detailed perspective view of the evaporator con- 'struction shown in Fig. 1; Fig. 3 is a detailed perspective view, in section, of the header for the evaporator shown in Fig. 1; Fig. 4 is a sectional view of the evaporator on the line l4 of Fig. 2, and Fig. 5 is a perspective view of a modified form of the evaporator shown. in Fig. 2. Referring now to the drawings, in Fig. 1 I have shown a household refrigerating machine including a cabinet having an outer wall I!) provided with a partition ll dividing the cabinet into an upper and a lower compartment Ila. A food compartment I2 is formed in the upper compartment by an inner wall or liner l3 spaced from the outer wall l0 and the partition H and provided with a heat insulated door or cover M. The space between the inner and outer walls is filled with heat insulation I5. A cooling unit or evaporator I6 secured to the inner wall I3 is provided to cool the chamber I2 and to freeze ice, desserts. or other comestibles. Refrigerant is supplied to the evaporator Hi from a motor and compressor unit arranged within a casing I! mounted on legs l8 within the lower compartment of the cabinet. Gaseous refrigerant is compresfed by a compressor within the casing l1 and is discharged through a. connection l9 communicating directly with the discharge port of the compressor to a condenser conduit 2|] secured on the inner surface of the outer wall ll] of the cabinet. Refrigerant-is partially condensed within the conduit 20 and passes through a tube 2| 5 to another condenser conduit 22 secured to the inner surface of the outer wall It] in the upper part of the cabinet. This condenser wherein a conduit is secured in heat exchange relationship to the outer wall of the refrigerator cabinet is 10 described and claimed in my copending application, Serial No. 554,623, filed August 3, 1931, and assigned to the General Electric Company, the assignee of my present invention. Liquid refrigerant condensed in the conduits 20 and 22 flows through a connection 23 to a receiver or float valve chamber 24. When a predetermined amount of liquid refrigerant has been collected in the chamber 24 a float valve therein operates to discharge the liquid through a conduit 25 to the evaporator IS. The liquid refrigerant is vaporized in the evaporator by the absorption of heat within the chamber l2 and the vaporized refrigerant fiows through a connection 26 to a separate spherical header 21 embedded in the insulation I5. A level of liquid refrigerant is maintained in the header 2! above the evaporator l6 so as to flood the same. The vaporized refrigerant which has collected in the spherical header 2! is withdrawn therefrom above the liquid level therein by the compressor through a suction conduit 28 and is returned to the casing l1, so that the casing is maintained at low pressure, and approximately at the same pressure as within the evaporator.

The evaporator I6 is constructed as shown in detail in Figs. 2, 3 and 4 and comprises two metal sheets 29 and 30 arranged face to face. The sheet 29 is provided with sinuous indentations or corrugations 3| and 32 connected by a plurality of indentations 33. The sheets are secured together in any suitable manner such as by line welding around the edges and between the indentations. The sheet 30 is made slightly larger than the sheet 29, and the edges thereof are bent around the edges of the sheet 29 after welding to form a smooth edge around the periphery of the sheets. The several indentations form passages between the sheets when they are secured together. The sheets are bent at a right angle to form an evaporator of inverted L- shaped cross-section, the indentation or passage 3| being in the vertical portion of the L and the passage 32 being in the horizontal portion of the L, which forms a shelf for freezing trays.

The evaporator I6 is secured in good heat exchange relation to the inner liner l3 of the cabinet on bolts |6a secured to the evaporator, which pass through holes in the liner l3 and are held by nuts |6b shown in Fig. 1. The refrigerant is admitted tothe passage 3| intermediate the ends thereof through a nozzle 34 at the ends of the connection 25, the nozzle being directed longitudinally of the passage to induce circulation of liquid refrigerant therein and thereby promote ebullition. The refrigerant within the conduit 3| is induced to flow upwardly and passes through the passages 33 to the conduit 32 in the horizontal or shelf portion of the evaporator from which it is discharged through the connection 26 and enters the side of the spherical header 21 as shown in Fig. 3. The spherical header 21 is maintained about half full of liquid refrigerant and is arranged so that it will always maintain a level of liquid refrigerant above the level of the passage 32 in the shelfportion of the evaporator, the liquid level being indicated at 35 in Fig. 1. Referring again to Fig. 3, a cylindrical extension 36 is provided at the bottom of the header 21 andcommunicates with the lower end of the passage 3| through a connection 31. This connection provides a return passage affording recirculation of liquid refrigerant through the passages 3| and 32 in the evaporator 16, the direction of flow being indicated by arrows. The refrigerant vaporized within the passages 3| and 32 flows with the circulating liquid refrigerant through the connection 26 to the header 21 where it collects and is withdrawn through the suction conduit 28 opening above the level of liquid refrigerant in the header.

During operation of the compressor within the casing 11 lubricating oil becomes entrained in the refrigerant and is discharged with the refrigerant into the condenser and passes to the float chamber and thence to the evaporator. This oil will collect and float on top of the liquid refrigerant in the header 21, and it is necessary that it be withdrawn and returned to the casing l1 in order to maintain the proper quantity of oil in the casing for lubrication of the compressor. It is also desirable that liquid refrigerant be prevented from returning with the oil to the casing. In order to return the oil to the casing without also returning liquid refrigerant, I provide a cylindrical baflie 38 surrounding the open end of the suction conduit 28 provided with end plates 39 having tubes 40 for securing the cylinder within the spherical header 21. The plates 39 are each provided with a round hole 4| and a slot 42 whereby liquid and gaseous refrigerant and oil are admitted to the interior of the cylinder 38. The cylinder 38 is arranged horizontally at right angles to the connection 26, so that gaseous and liquid refrigerant entering the header from the evaporator l6 and boiling of refrigerant do not disturb the liquid within the cylinder. The cylinder thus maintains a quiet zone within the header and the oil floating on top of the refrigerant is withdrawn through the suction conduit 28 as soon as a sufiicient quantity of oil is collected to reach the top of the conduit. Since turbulence of the liquid refrigerant is prevented within the cylinder 38, and since the level of refrigerant is maintained below the open end of the conduit 28'by operation of the refrigerating machine, liquid refrigerant is prevented from entering the suction conduit 28. The arrangement whereby a closed cylinder having an opening at the end thereof is secured about the end of the suction conduit to provide a quiet zone within the header is described and claimed in a copending aplication of C. H. Steenstrup, Serial No. 38,204, filed August 28, 1935, and assigned to the General Electric Company, the assignee of my present application; and the particular arrangement of a cylinder mounted horizontally at the end of the suction line and provided with plates at its ends having slots extending above and below the level of liquid refrigerant in the header is described and claimed in a copending application of L. W. Atchison, Serial No. 38,187, filed August 28, 1935, and also assigned to the General Electric Company. I do not, therefore, herein claim anything claimed in the said C. H. Steenstrup or L. W. Atchison applications which are to be regarded as prior art with respect to this present application.

The refrigerating machine may be controlled to maintain a proper temperature of the evaporator by operation of any suitable temperature responsive element which is arranged within a tube 43 projecting upwardly into the cylindrical projection 36 of the header at the side of the suction conduit 28.

InFig. 5 of the drawings I have shown a modified form of evaporator which is to be connected to theheader of the construction shown in Fig. 3 in the same manner as the evaporator shown in Fig. 2. The evaporator shown in Fig. 5 comprises two plates 44 and 45 secured together face to face by any suitable method, such as line welding, the edge of the plate 45 being bent over the Welded edge of the plate 44 and the sheets being bent at an angle to form an inverted L- shaped evaporator in the same manner as that shown in Fig. 2. The lower or vertical portion of the evaporator is provided with a passage 46 formed by a sinuous indentation in the plate 44 and with a short vertical passage 41, these passages being connected at their upper ends by a sinuous passage 48 formed by an indentation in the plate 44 in the upper or shelf portion of the evaporator. evaporator from the conduit 25 connected to the lower end of the passage 41. circulation of refrigerant through the passage 46 a small duct 49 is provided connecting the passage 41 to the passage 46, so that a jet of liquid refrigerant will be directed along the passage 46 and will produce an upward circulation of refrigerant therein. It will thus be seen that liquid refrigerant will circulate upwardly through the passage 46, and also upwardly through the passage 41, and thence through the passage 48 in the shelf portion of the evaporator. The connection 26 to the header 21 communicates with the passages 46 and 48 at 26a. in the upper-end of the passage 46 in the vertical portion of the evaporator, and the return or recirculating connection 31 leading from the extension 36 on the header is connected to the end of the passage 46 at 50, so that liquid refrigerant is recirculated through the passage 46.

During operation of this modified form of evaporator shown in Fig. 5, the greater portion of liquid refrigerant admitted through the conduit 25 from the float valve chamber 24 flows upwardly through the passage 41 and through the passage 48 in the freezing tray shelf where it is available to rapidly absorb heat for the purpose of freezing water in trays placed on the shelf.

Refrigerant flowing through the passage 46 is for Refrigerant is admitted to the In order to induce the most part recirculated refrigerant flowing through the passage 26 into the header and through the extension 36 of the header and back to the passage 46, circulation being induced by the jet of liquid refrigerant admitted to the passage 46 through the duct 49.

From the foregoing it will readily be apparent that I have provided an improved evaporator for refrigerating machines which requires a minimum of space within the compartment to be cooled and which provides an adequate circulation of liquid refrigerant for cooling the air in a compartment and for freezing ice.

While I have shown my invention as applied to a household refrigerating machine, I do not desire my invention to be limited to the particular construction shown and described, and I intend in the appended claims to cover all modifications within the spirt and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. In a refrigerating machine of the type including a cabinet having a cooling compartment accessible from the top thereof, a flooded evaporator of inverted L-shaped form having a horizontal freezing shelf and a vertical air cooling portion, said shelf being accessible from the top thereof, and means for maintaining a. level of liquid refrigerant above the level of said shelf.

2. In a refrigerating machine, a flooded evaporator of inverted L-shaped form having a horizontal freezing shelf and a vertical air cooling portion, means introducing liquid refrigerant into said vertical portion for producing a circulation of liquid refrigerant through said vertical portion and through said shelf, and means for providing a return passage affording recirculation of liquid refrigerant through said vertical portion.

3. In a refrigerating machine, a flooded evaporator comprising two portions, each of. said portions having a passage therein, means affording recirculation of liquid refrigerant through one of said portions, means for supplying liquid refrigerant to said evaporator through the passage in the other of said portions; and means providing communication between said supply means and the passage in said one portion for diverting part of the liquid refrigerant from said supply means to said one portion and for producing recirculation of liquid refrigerant in said one portion.

4. In a refrigerating machine, a flooded evaporator comprising a vertical portion and a shelf portion, each of said portions having a passage therein, means affording recirculation of liquid refrigerant through said vertical portion, means for supplying liquid refrigerant through the passage in said shelf portion to said vertical portion, and means diverting part of the liquid refrigerant supplied through said shelf portion for producing recirculation of liquid refrigerant in said vertical portion.

5. In a refrigerating machine, a flooded evaporator of L-shaped form having a horizontal freezing shelf and a vertical air cooling portion, means affording recirculation of liquid refrigerant through said vertical portion, means including a passage in said vertical portion for supplying liquid refrigerant through the passage in said shelf to said vertical portion, means diverting part of the liquid refrigerant from said passage for producing recirculation of liquid refrigerant in said vertical portion.

6. In a refrigerating machine, a flooded evaporator of inverted L-shaped form having a horizontal freezing shelf and a vertical air cooling portion, means introducing liquid refrigerant into said vertical portion for producing a circulation of liquid refrigerant through said portion and through said shelf, means for maintaining a level of liquid refrigerant above the level of said shelf, and means for providing a return passage affording recirculation of liquid refrigerant through said vertical portion.

. 7. In a refrigerating machine, a flooded evaporator of L-shaped form in cross-section and having a flat vertical portion and a flat horizontal portion, each of said portions having a refrigerant passage therein, means for providing communication between said passages, means introducing liquid refrigerant into said evaporator intermediate the ends of the passage in said vertical portion for inducing a circulation of refrigerant therein and in said horizontal portion, and means providing a return passage affording recirculation of refrigerant through the passage in said vertical portion.

8. In a refrigerating machine, a flooded evaporator of L-shaped form having a vertically extending portion and a horizontally extending portion, each of said portions having a sinuous passage therein, means for providing communication between said passages, means introducing liquid refrigerant intermediate the ends of the sinuous passage in said vertically extending portion for providing an upward circulation of refrigerant therein, and means for providing a return passage affording recirculation of liquid refrigerant through both of said passages.

9. In a refrigerating machine, a flooded evaporator of L-shaped form having a vertically extending portion and a horizontally extending portion, each of said portions having a sinuous passage therein, means including another passage in said vertically extending portion communicating with one end of the sinuous passage in said horizontally extending portion and with the sinuous passage in said vertically extending portion for producing a circulation of liquid refrigerant through said sinuous passages, and means for providing a return passage affording recirculation of liquid refrigerant through the sinuous passage in said vertically extending portion.

10. In a refrigerating machine, an evaporator of inverted L-shaped form having a horizontal freezing shelf portion and a vertical air cooling portion, means introducing liquid refrigerant into said evaporator for producing a circulation of refrigerant in said shelf and in said air cooling portion, and means including a header separate from said portions for providing recirculation of liquid refrigerant through said air cooling portion.

11. In a refrigerating machine, an evaporator of inverted L-shaped form having a horizontal freezing shelf portion and a vertical air cooling portion, means introducing liquid refrigerant into said evaporator for producing a circulation of refrigerant in said shelf portion and in said air cooling portion, means including a header for maintaining a level of liquid refrigerant above the level of said shelf, and means including an extension on said header for providing a recirculation of liquid refrigerant through said air cooling portion.

12. In a refrigerating machine, an evaporator of L-shaped form comprising sheets of metaLsecured face to face and having a horizontal freezing shelf portion and a vertical air cooling portion, said shelf having a passage formed between said sheets, said vertical portion having a plurality of horizontal passages formed between said sheets, means introducing refrigerant into said evaporator for producing an upward circulation in the passage in said vertical air cooling portion, means connecting said passages for providing communication between the passage in said shelf and the passages in said vertical portion, and means for returning refrigerant from said shelf to the passage in said vertical portion.

13. In a refrigerating machine, a flooded evaporator of L-shaped form comprising sheets of metal secured face to face and having a vertical air cooling portion and a horizontal freezing shelf portion, each of said portions having passages formed therein between said sheets, means introducing liquid refrigerant into the passage in said vertical portion for producing an upward circulation of refrigerant therein, means for providing communication between the passages in said portions, and means for maintaining a level of liquid refrigerant above the level of said shelf portion and for returning liquid refrigerant from said shelf portion to said vertical portion.

14. In a refrigerating machine, a flooded evaporator of L-shaped' form comprising sheets of metal secured face to face and having a vertical air cooling portion and a horizontal freezing shelf portion, each of said portions having passages formed therein between said sheets, means introducing liquid refrigerant into the passage in said vertical portion for producing an upward circulation of refrigerant therein, means providing communication between the passages in said portions, means including a header for maintaining a level of liquid refrigerant above the level of said shelf portion, and means including an extension on said header communicating therewith for producing a recirculation of liquid refrigerant through the passage in said vertical portion.

15. In arefrigerating machine, a flooded evaporator for refrigerating machines of thetype in which lubricating oil may circulate with the refrigerant including a refrigerant circulating passage, means including a spherical header for maintaining a level of liquid refrigerant above the level of said passage, means including a cylindrical extension on said header .for providing a recirculation of liquid refrigerant through said passage, and means including a suction conduit entering said cylindrical extension for withdrawing vaporized refrigerant from said header.

16. In a refrigerating machine, a flooded evaporator for refrigerating machines of the type in which lubricating oil may circulate with the refrigerant including a refrigerant circulating passage, means including a spherical header for maintaining a level of liquid refrigerant above that of said passage, means including a cylindrical extension on said header for providing recirculation of said liquid refrigerant through said passage, means including a suction conduit entering said cylindrical extension for withdrawing vaporized refrigerant from said header, and means including a cylindrical baffle supported within said header and extending about the end of said suction conduit for admitting lubricating oil to said conduit and for preventing the admission of liquid refrigerant thereto.

17. A refrigerating machine comprising a cabinet having inner and outer walls spaced apart and provided with heat insulation therebetween, means including a refrigerant circulating passage secured in heat exchange relation to said inner wall and having a portion extending from said inner wall for cooling theair within said cabinet and for providing a freezing shelf within said cabinet, means for maintaining a predetermined level of liquid refrigerant within said passage, and means injecting liquid refrigerant below the level of liquid refrigerant in said passage for promoting ebullition of the liquid within said passage.

18. A refrigerating machine comprising a cabinet having inner and outer walls spaced apart and provided with heat insulation therebetween, means including a refrigerant circulating passage secured in heat exchange relation to said inner wall and having a portion extending from said inner wall for cooling the air within said cabinet and for providing a freezing shelf within said cabinet, means for supplying liquid refrigerant to said passage, and means embedded in the insulation between said walls for maintaining a level of liquid refrigerant above the level of said passage and for providing a recirculation of liquid refrigerant through a portion of said passage.

19. A refrigerating maching comprising a cabinet having inner and outer walls spaced apart and provided with heat insulation therebetween, means including a refrigerant circulating passage secured in heat exchange relation to said inner wall and having a portion extending from said inner wall for cooling the air within said cabinet and for providing a freezing shelf within said cabinet, means for supplying liquid refrigerant to said passage, and means including a header embedded in the insulation between said walls for maintaining a level of liquid refrigerant above the level of said passage and for providing a recirculation of liquid refrigerant through a portion of said passage.

20. A refrigerating machine including a cabinet comprising inner and outer walls spaced apart and having heat insulation arranged therebetween, a flooded evaporator of L-shaped form having one portion secured in heat exchange relation to said inner wall of said cabinet and another portion forming a shelf for freezing trays extending from said inner wall into said cabinet, means for supplying liquid refrigerant to both portions of said evaporator and for producing a circulation of liquid refrigerant through said evaporator, and means including a header embedded in the insulation between said walls for maintaining a level of liquid refrigerant above the level of said shelf and for providing recirculation of liquid refrigerant through said evaporator. v

21. A refrigerating machine including a cabinet comprising inner and outer walls spaced apart and having insulation arranged therebetween, an evaporator of L-shaped form having one portion secured in heat exchange relation to said inner wall of said cabinet and another portion forming a shelf for freezing trays extending from said inner wall into said cabinet, means for supplying liquid refrigerant to both portions of said evaporator and for producing a circulation of liquid refrigerant through said evaporator, and means including a spherical header having a cylindrical extension thereon and communicating therewith for maintaining a level of liquid refrigerant above the level of said shelf and for providing recirculation of liquid refrigerant through said evap CHRISTIAN STEENSTRUP.

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